Feed mechanism for sewing machines



June 4, 1940. HACKLANDERI AL 2,203,386

FEED MECHANISM FOR SEWING MACHINES Filed Sep t. 19 i936 4 Sheets-Sheet 1' "j I w I WITNESSES: INVENTORS:

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June 1940- H. HACKLANDER El l. 2,203,386

FEED MECHANISM FOR SEWING MACHINES Filed Sept. 19, 1938 4 Sheets-Sheet 2 W] TNESSEE:

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H. HACKLANDER El AL 03,386.

4 Sheet-Sheet 5 Filed Sept. 19, 1935 INVENTORS:

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June 4, 1940.

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FEED MECHANISM FOR SEWING MACHINES Filed Sept. 19, 1936 4 Sheets-Sheet 4 I WITNESSES: I INVENTORS:

59 Lhf iiims ifizcklaiuizr 6:. g N y Harold .I 1757455502224 M 04] h Q l L 5 A RNEYS.

Patented June 4, 1940 UNITED STATES PATENT OFFICE FEED MECHANISM FOR SEWING MACHINES Application September 19, 1936, Serial No. 101,589

14 Claims.

This invention relates to feed mechanism for sewing machines; and it has reference more specifically to a differential feed mechanism particularly advantageous in feed-off-thearm sewing machines of the type disclosed in another application Serial Number 101,588 filed by us concurrently herewith.

In connection with differential feed mechanisms for sewing machines generally, we aim to provide simplified and structurally improved facilities for' imparting the necessary vertical and longitudinal movements to the feeddogs.

Another object of our invention is to secure more perfect balance and to reduce the momentum of the component parts of such mechanism with a view toward eliminating vibration and'favoring operation of the sewing machines at higher speeds than heretofore attainable.

Another object of ourinvention is to provide improved means capable of adjustment to change the differential movements of the feed dogs so' thatthe sewing machine may be adapted for operation upon different materials.

Other objects and attendant advantages will appear from the detailed description following of the drawings wherein:

Fig. I is a fragmentary plan view of a sewing machine embodying our improved feed mechanism.

Fig. II is a view partly in front elevation and partly in vertical section of the machine taken as indicated by the arrows 11-11 in Fig. I.

Fig. III is a fragmentary View of the machine partly in front elevation and partly in longitudinal section taken as indicated by the arrows III III in Fig. I.

Fig. IV is a view partly in plan and partly in section taken as indicated by the arrows IVIV in Fig. II showing the work supporting arm with the cover members removed to expose the enclosed parts of the feed mechanism.

Fig. V is a fragmentary detail view looking as indicated by the arrows VV in Fig. IV.

Fig. VI is a fragmentary plan view of the front end of the work supporting arm.

Figs. VII and VIII are plan views of the two feed dogs.

tuting the subject of the copendingapp-lication Serial No. 101,588, hereinafter referred to. As shown, the frame I of the machine has a fiat base 2 adapted to rest on a work bench or table, and an integrally formed, laterally-projecting bracket portion 2a supporting, at an elevation, a longitudinal sleeve portion 3. In this sleeve portion 3 of the frame is journaled a main shaft 4 from which the stitching, looping, and trimming mechanism, as Well as the feed mechanism of our invention all derive motion. Secured by screws 5 to a pendant hollow portion 6 (Fig. II) at the righthand end of the frame I is a hollow work support in the form of an arm 1 which extends at an acute angle (see Fig. I) relative to the sleeve portion 3 at a level below the same (see Fig. II). The outer or left hand end of the arm 1 is overreached by a head 8 projecting laterally from the corresponding end of the frame. To the left hand protruding end of the main shaft 4 is affixed a pulley 9 adapted to be coordinated by a belt, not shown, with a source of power of any usual type; and within the hollow of the frame I, said main shaft carries a miter gear I0, which, through an intermeshing miter gear ll, imparts rotation in unison to a countershaft l2 journaled in suitable bearings within the head 8.

Through the link connections shown at l3 and M (Fig. II) the necessary loop taking and needle avoidingmovements are imparted to the loopers l5 and I6 of the machine, said loopers operating above the work support 1. Also through movement derived from the countershaft l2 an arm I! carrying a cutting blade [8 is occillated horizontally about the presser bar of the machine to trim upstanding abutted margins of the fabric which is to be seamed as it is progressed along the work support. The sewing needles 2| and 22 of the machine are secured in a carrier arm 23 which is fulcrumed to oscillate about a transverse pin 24 at the forward end of the work,

support I, said needles being adapted to penetrate the fabric from beneath. The actuating connections for swinging the needle arm 23 include a link 25 which extends horizontally through the hollow of the work-support and which has its rear end pivotally connected to the pendant arm 26a of a bell crank 26 (Figs. II, IV, and X) mounted to oscillate about a transverse pin 21 at the rear end of said work support, the other arm 26b of said bell crank being coupled by means of a vertical pitman 28 with an actuating crank 29 on the main shaft 4, see Figs. II and III.

The feeding mechanism with which the present invention is more especially concerned includes a main feed dog 30] and an auxiliary feed dog 3!, to cooperate with the presser foot 32 of the machine, said dogs having teeth pitched so as to feed the fabric forwardly or off the work support 1 incident to being actuated in a manner present ly explained. The toothed faces of the feed dogs project up through slots in the throat plate 33 of the machine which is removably secured to the work support I at the outer end thereofby screws, see Fig. VI. The feed dogs 3%, it will be observed from Fig. IV, are formed with squared shanks 34 and 35 which are guided and confined against rotation by wear plates 35 and 3? at opposite sides of the work support. The feed dogs 30 and 3! are respectively securedat their shank ends by screws 38 and to main auxiliary feed bars Ml, 4| which are substantially coextensive, and which, for the sake of lightness are made tubular. Medially of their ends, the feed bars 40, ll are engaged with capacity for endwise sliding, in a rocker 42 fulcrumed about the eccentric portion 53 of a pin 4% extending transversely of the work support. Obviously, by rotational adjustment of the pin M it is possible to shift the orbital movement of the feed dogs vertically. A 'set screw 35 serves to hold the fulcrum pin M in adjusted positions. To the rear or right hand end of the main feed bar is secured a clevis 46 with an upward projection 67 affording a pivotal connection 48 with the lower end of a vertical pitman 49 which, at its upper end is connected to an eccentric 59 on the main shaft t. Accordingly, during each rotation of the main shaft 4 both the feed dogs 3!, 32, are moved up and down about the pivot pin Ml since both of them are supported by the rocker A2. Endwise movements are imparted to the feed bars ill, Ail through mechanism which includes a bell crank 5! (Figs. II, IV, X and XII) loosely mounted on the cross pin 2'1 herein before referred to, said bell crank having a pendant arm 5 la coupled by means of a horizontal link 52 with the clevis 46 at the right hand end of the main feed bar 40, and a horizontal arm 5H1 having a pivotal connection 53 intermediate its ends with the lower end of another vertical pitman 55. At its upper end the pitman 55 is connected to a crank 56 at the right hand end of the main shaft as shown in Figs. I and III. To the outer end of the horizontal arm 5H) of the bell crank 59 is pivoted a drop link 58 which is serially coupled by means of a horizontal link 59 with a cross head which is secured to the right hand end of the auxiliary feed rod ll, and which has sliding engagement with the main feed bar ill. The pivotal connection 6! between the links 58 and 59 is suspended by means of a lazy bar 52 from the end of an angularly adjustable arm 63 having an integral axial fulcrum lug 64 journaled in the side wall 65 of the work support I. Tothe protruding end of the fulcrum lug 64 is secured, by means of a screw 65, a manipulating disk 61!. As shown in Fig. V, this disk 6? is provided with a grasp projection 68 and on its outer face has a concentric annular recess for a pair of opposing circumferentially adjustable arcuate stops 59, 10 which are adapted to cooperate with a headed pin H. The shank of this headed pin 7!, see Figs. IV and V, passes through an arcuate slot 12 in the'disk 6'! and through an anchorage aperture 73 in the side wall 65 of the work support 1. A compression spring 14 interposed between the inner face of the side wall just referred to and a nut 15 on the inner end of the pin ll, serves to hold the disk 5! in frictionalengagement with the wall 65 and thereby prevents it from being accidentally shifted. By rotating the disk 6'! in the direction of the arrow in Fig. V and correspondingly swinging the arm 63 from the dotted to the dot and dash line position as far as permitted by coaction of the stop 70 with the pin H, the movement of the auxiliary feed rod 4| may be decreased from a maximum to a minimum amount while the machine is operating, the change thus occasioned in the movement of the auxiliary feed dog 3i being always proportional to that of the main feed dog 30 which has a fixed axial throw. In other words, if the main feed dog is given a feed stroke of one eighth of an inch and the diiferential feed is set at a two to one ratio to the stroke of the main feed, then any change in the stroke of the main feed will effect a corresponding proportional change in the stroke of the difierential feed.

The feed bars 40 and 4! are relatively lightby virtue of being tubular, and well balanced since they are substantially of the same lengthand medially supported in the rocker 42. Moreover, the actuating connections between the main shaft 5 and the feed bars MI and M are simple, and also comparatively light and well balanced. The momentum due to the action of the. parts constituting our improved feed mechanism is thus reduced to a minimum, so that the sewing machine can be operated at very high speeds without attendant vibration and noise.

The use of feed bars 40 and 4| of circular cross section instead of square section is advantageous in that it simplifies machining of the parts into which these rods engage or Slidingly fit, with at tendant reduction in the costs of manufacture,

and assurance of greater accuracy in the feeding ily adapted, by suitable modifications within the scope of the appendedclaims, to other types of sewing machines, with attainment of advantages equal in all respects to those hereinbefore pointed out.

Having thus described our invention, we claim:

1. Feed mechanism for sewing machines, including a pair of parallel feed bars respectively carrying main and auxiliary feed dogs, a supporting rocker common to the two feed bars swingable about a transverse pivot and confining them for independent longitudinal sliding movement in a common horizontal flame, means to oscillate the rocker for impartation of up and down movements to the feed dogs, and means for concurrently inducing differential longitudinal movements in the feed bars.

2. Feed mechanism for sewing machines, comprising a pair of parallel feed'bars respectively carrying main and auxiliary feed dogs, a supporting rocker common to the two feed bars swingable about an eccentric portion of a rotativelyadjustable transverse pivot pin, and confining the feed bars for independent longitudinal sliding movement in a common horizontal flame, means to oscillate the rocker for impartation of up and down movements to the feed dogs, and means for concurrently inducing 'difierential longitudinal movements in the feed bars.

3. Feed mechanism for sewing machines, comprising a pair of parallel cylindric feed bars respectively carrying main and auxiliary feed dogs, a rocker swingable about a transverse pivot and supporting the feed bars with capacity for independent longitudinal sliding, means to prevent rotation of the feed bars in the rocker, means to oscillate the rocker for impartation of up and down movements to the feed dogs, and means for concurrently inducing differential longitudinal movements in the feed bars.

4. Feed mechanism for sewing machines, comprising a pair of parallel cylindric feed bars respectively carrying main and auxiliary feed dogs with fiat sided shanks, a rocker swingable about a transverse pivot and supporting the feed bars with capacity for independent longitudinal sliding, guide plates cooperating with the flat sides of the feed dog shanks to prevent rotation of the feed bars in the rocker, means to oscillate the rocker for impartation of up and down movements to the feed dogs; and means for concurrently inducing differential longitudinal move ments in the feed bars.

5. Feed mechanism for sewing machines, comprising a pair of parallel tubular feed bars respectively carrying main and auxiliary feed dogs; a rocker swingable about a transverse pivot and supporting the feed bars with capacity for independent longitudinal sliding; ,means to oscillate the rocker for impartation of up and down movements to the feed dogs; and means for inducing differential longitudinal movements in the feed ,bars.

6. Feed mechanism for sewing machines, comprising a pair of parallel tubular cylindric feed bars respectively carrying main and auxiliary feed dogs, a rocker swingable about a transverse pivot and supporting the feed bars with capacity for independent longitudinal sliding, means to prevent rotation of the bars in the rocker, means to oscillate the rocker for impartation of up and down movements to the feed dogs; and means for concurrently inducing differential longitudinal movements in the feed bars.

7. Feed mechanism for sewing machines in-- cluding a pair of parallel feed bars respectively carrying main and auxiliary feed dogs at their forward ends, a rocker swingable about a transverse pivot and supporting the feed bars medially with capacity for independent longitudinal sliding, means connected to the rear end of one of the feed bars to impart up and down movement thereto for communication in like degree to the other feed bar through the rocker; and means for concurrently inducing differential longitudinal movements in the feed bars.

8. Feed mechanism for sewing machines including a pair of substantially-coextensive parallel feed bars respectively carrying main and auxiliary feed dogs at their forward ends, a rocker swingable about a transverse pivot and supporting said bars medially with capacity for independent longitudinal sliding, means connected to the rear end of one of the bars to impart up and down movement thereto for communication in like degree to the other feed bar, means for inducing a fixed longitudinal movement in one of the feed bars; and means deriving movement from the last mentioned means and connected to the rear end of the other feed bar longitudinal sliding, means to oscillate the rocker for impartation of up and down-movements to the feed dogs, an oscillating bell crank lever with a vertical arm link-connected to the rear end of the main feed bar for impartation of a fixed throw to the latter, serially-arranged hori zontal and vertical links connecting the rear end of the auxiliary feed bar with a horizontal 'arm of the bell crank lever aforesaid, a lazy bar supporting the connecting pivot of the serial links, and an angularly adjustable arm from the end of which the lazy bar is pivotally suspended.

10. Feed mechanism for sewing machines, comprising a pair of substantially-coextensive parallel feed bars arranged side by side and respectively carrying main and auxiliary feed dogs at their forward ends, a rocker swingable about a transverse pivot axis and supporting the feed bars medially with capacity for independent longitudinal sliding, means to oscillate the rocker for impartation of up and down movements to the feed dogs, an oscillating'bell' crank with a vertical arm link-connected to the rear end of the main feed bar to impart a fixed throw to the latter, a cross head secured to the rear end of the auxiliary feed bar and having sliding engagement with the main feed bar, serially arranged horizontal and vertical links connecting the cross head with a horizontal arm of the bell crank lever aforesaid, a lazy bar supporting the connecting pivot center of the two links, and an angularly-adjustable arm from the end of which the lazy bar is pivotally suspended.

11. In a sewing machine, a frame with a longitudinal hollow, a hollow work support below the longitudinal hollow aforesaid and communicating therewith through a connecting vertical hollow, a drive shaft longitudinally within the hollow of the frame, and feed mechanism including a pair of parallel horizontal feed bars arranged side by side within the hollow of the work-support and respectively carrying main and auxiliary feed dogs at their forward ends, a rocker swingable about a pivot axis transversely of the work support and sustaining the feed bars medially with capacity for independent longitudinal sliding, actuating connections extending down through the vertical connecting hollow aforesaid from the shaft to the inner end of one of the feed bars to impart up and down movement to said bar for communication in like degree to the other bar through the rocker, a bell crank lever fulcrumed about a cross pin within the inner end of the work-support and connected through the vertical frame hollow with actuating means on the shaft, a horizontal link coordinating the rear end of the main feed bar with a vertical arm of the bell crank for impartation of a fixed throw to said bar, serially-arranged horizontal and vertical links connecting the rear end of the auxiliary feed bar with a horizontal arm of the bell crank, a lazy bar supporting the connecting pivot of the serial links, and an arm angularly adjustable in the side of the work support from the end of which the lazy bar is pivotally suspended.

12. In a sewing machine, a frame with a longitudinal hollow, a hollow work support below the longitudinal hollow aforesaid and communicating therewith at one end through a vertical hollow, a drive shaft longitudinally within the hollow of the frame, and feed mechanism including a pair of coextensive horizontal tubular feed bars arranged side by side within the hollow of the work support and respectively carrying main and Ill auxiliary feed dogs at their forward ends, a 75 rocker swingable about a pivot axis transversely of the work support and sustaining the feed bars medially with capacity for independent longitudinal sliding, a bell crank lever fulcrumed on a cross pin Within the work support at the rear end thereof, an actuating connection extending from the main shaft downward through the vertical hollow aforesaid to the bell crank lever, a horizontal link coordinating a vertical arm of the bell crank lever with the rear end of the main feed bar for impartation of a fixed throw to the latter, a cross head secured to the rear end of the auxiliary feed bar and slidingly engaging the main feed bar, serially-arranged horizontal and vertical links connecting the cross head with a horizontal arm of the bell crank lever aforesaid, a lazy bar supporting the connecting pivot of the serial links, and an arm angularly adjustable in the side of the work support from the end of which the lazy bar is pivotally suspended.

13. Feed mechanism for sewing machines, in-

cluding a bar carrying a feed dog, a rocker swingable about a transverse pivot and havingan opening therein offset from the plane of the pivot in which the bar is guided for longitudinal sliding movement, means connected to the feed bar for oscillating the rocker to impart up and down movement to the feed dog, and means for concurrently inducing longitudinal movement of the bar.

14. Feed mechanism for sewing machines, including a bar of cylindric cross section carrying a feed dog, a rocker swingable about a transverse pivot and supporting the bar with capacity for longitudinal sliding movement; means connected to the feed bar for oscillating the rocker to impart up and down movement to the feeddog, means for concurrently inducing longitudinal movement of the bar, and means for guiding the feed dog and holding the bar against rotation in the rocker. V

' HANS HACKLANDER.

HAROLD J. LE; VESCON'IEl 

